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Latvia is one of the largest exporters of pellets in Europe, and at the same time share of biofuel in energy production in Latvia is also one of the largest between the developed countries. Rapid increase of biofuel production and export raises questions about sustainability of forest sector and contribution of the forest biofuel produced in Latvia to the greenhouse gas (GHG) balance in Europe. Sustainability of forest biofuel is broadly discussed issue in Baltic states; particularly, due to continuous increase of production and export of wood pellets. GHG mitigation potential of the forest biofuel is one of the sustainability aspects surrounded by multiple speculations, which has to be addressed by comprehensive comparison of GHG fluxes due to production and use of forest biofuel and substituted fossil fuel. Assessment of the GHG mitigation potential of forest biofuel is complex process requiring multiple activity data and assumptions. Particular complexity of calculation is determined by the need to use harmonized approach for the whole calculation period. The assessment of the climate change mitigation in this study is based on the methods applied in National GHG inventory and literature data on GHG emissions due to production and delivery of substituted fossil fuel and forest biomass including demolition wood. According to the study results substitution effect of the forest biofuel in Latvia continuously increases since 2000, mainly due to export of biofuel, reaching 14323 Gg CO2 eq. in 2020 (by 30% more than the net GHG emissions in Latvia in 2019). Electricity production in pellet factories, in spite of major reduction of GHG emissions in the production process, has minor role in the total substitution effect. [ABSTRACT FROM AUTHOR]

In daily logging practice, there are many cases, when it is not possible to choose the right forwarder type for the working conditions in the felling area and the amount of timber transported. Then consequences are unacceptable: too deep ruts made by the wheels of the forwarder or complete impossibility to use the forwarder as a timber transport vehicle. That is a problem difficult to solve, because the amount of previous research is not sufficient to create a universal and practically available method to obtain credible characteristic of ground bearing capacity. To determine the effect of the timber forwarder on peat soil by various methods, depending on its payload utilization and the amount of branches used to reinforce the road, the observation method takes place in the felling area purposely prepared for such research. Measurements of soil resistance and depth of the ruts in the study site with the amount 50 kg⋅m-2 of logging residues for the strengthening mat on technological strip show that the forwarder movement is possible. To predict the possibility of round timber primary transport by a forwarder under production conditions, it is necessary to evaluate the soil shear resistance, as a positive correlation between this parameter, and the depth of the ruts in the given study. [ABSTRACT FROM AUTHOR]

The topicality of the study is determined by the increasing demand for sanitary felling services currently mainly provided by manual work. Harvesting using hand-held motor instruments is a physically hard work whose costs are increasing rapidly, but labor availability is declining. In sanitary cuttings, additional complications are caused by the use of conventional machinery in harvesting, which necessitates the creation of wide (4 m) technological corridors and significantly increases the proportion of damaged remaining trees in a stand (according to past studies, a set of middle-class forest machines in thinning of spruce stands results in 4–5% of damaged trees, but in pine stands – in approximately twice less damaged trees than in spruce stands). The compact class forest machines in thinnings result in mechanical damage to not more than 1% of remaining trees. During field trials in sanitary felling 9329 trees were felled. The average productivity working in one shift is 5.35 m3 h-1 with average stands 10 cm. The cost of harvester’s productive hour is 92 € but of a forwarder it is 78. The compact class forwarder creates significantly smaller impact on the soil by reducing ruts depth and soil compaction, which is especially important in sanitary fellings and extraction of seed trees in regenerated areas. [ABSTRACT FROM AUTHOR]

The aim of this study is to compare productivity and costs of medium-sized and small-sized harvesters in pre-commercial thinning. In this study the data on harvesting productivity were obtained in stands, where biofuel was prepared using two medium-sized and two small-sized harvesters equipped with different harvester heads. In total 677 m3 of wood was prepared with medium-sized harvester, but with small-sized harvesters 1 164 m3 of wood was prepared. Although the total annual costs of small-class harvesters are lower by 16%, comparing with middle-class harvesters, the productivity rates shown by the middle-class harvester John Deere 1070 E (equipped with H 754 harvester head) are significantly higher and the average wood preparation costs are lower, comparing with the other harvesters employed. [ABSTRACT FROM AUTHOR]

With the increasing demand for renewable energy in the domestic market, additional attention is paid to the use of stump-wood in energy supply. The stump harvesting technology is not substantiated sufficiently so that the end users can use this unpredictable raw material to generate heat and power. Service providing logging companies need to know the specific requirements to equipment and the characteristics of stump harvesting technologies in order to assess the possibility of acquiring this natural resource. The stump harvesting should be planned along with the regenerative felling, because the layout of the timber forwarding roads and the characteristic of the logging residues layer on the road surface are important. In its turn, when planning the upper timber yard, it is necessary to take into account the meteorological data, the prevailing wind direction and water streams. The aim of the study is to find out the total energy balance during the stump extraction with the MCR500 bucket. Working time, output volumes and productivity indicators are derived from the project "Development and testing of a prototype of multifunctional equipment for stump-wood production and preparation of the soil mounds" (2DP/2.1.1.1.0/10/APIA/VIAA/174) results and from the results of the joint stock company "Latvia state forest" project implemented in 2008. The most energy-consuming process is comminution of biomass, therefore it is common, for instance, in Finland that electricity-operated equipment located near the customer is used to carry out this work. More efficient use of forest resources by stump extraction and further utilization in heat and power production can increase biomass deliveries for energy applications by 500 thousand tons of dry matter of currently unused coniferous stump biomass annually. [ABSTRACT FROM AUTHOR]

The research aim is to estimate the profit a forest owner can earn per full forest rotation cycle from forest stands of dominant coniferous species in Latvia, selling both the assortment of logs and biomass (BM) from final felling. The research analysed the situation in privately managed forests, composed of the coniferous species - Norway spruce (Picea abies L.) and Scots pine (Pinus syllvestris L.) - in different forest types in Latvia. The calculation of revenue from forest product sales took into account both the direct revenue from the sales of the assortment of logs and of tree BM, including branches and stumps, obtained from logging. The research found that the management of pine forest stands generated a profit from 2.7 to 8.2 thou. EUR ha-1 per rotation cycle for the owner, depending on the forest type. The highest revenue from growing pine stands was generated in the forest type Hylocomiosa. The management of forest stands where spruce was the dominant species generated a profit from 7.9 to 9.6 thou. EUR ha-1 per rotation cycle. The highest revenue from growing spruce stands was generated in the forest type Myrtilossa mel. If selling BM, marginal extra revenue may be generated: 2-7% from pine stands and 4-5% from spruce stands. It can be expected that with rising consumption of biofuels in future the price of energy wood will rise, increasing the profit for forest owners. [ABSTRACT FROM AUTHOR]

Forest plays a multifaceted role, which is determined by its economic, ecological and social values; therefore, sustainable forestry development has to ensure a balanced use of all the values. For the first time in Latvia, the situation in hunting management was analysed, assessing the level of safety and traumatism. The research aim is to assess safety in the process of hunting and the real situation in Latvia. The research found that the most dangerous kinds of hunting were hound hunting and waterbird hunting during their autumn migration. In the period 1969-2016 in Latvia, 268 individuals suffered from hunting-related accidents; of them, 80 or 30% of the total lost their lives, making a EUR 39 million loss to the national economy. In this period, 126 hunting accidents or 47% of the total were severe or moderate, in which an individual lost the ability to work or became disabled. Since 2000, the safety of hunting has improved, as the number of deaths and serious accidents in hunting has decreased. In Latvia, 45% of the total number of surveyed hunters faced a situation where their lives or health were endangered but there was no accident. An analysis of unreported hunting-related traumatism showed that every hunter suffered a trauma during hunting or hunting area maintenance works. An analysis of the kinds of traumas revealed that minor body injuries prevailed, yet some of the hunters received moderate and severe injuries during hunting (extensive tissue damage, broken bones). In general, one can conclude that the environment for hunting is safe in Latvia, which was mentioned by 66% of the hunters; however, a greater focus has to be placed on observing the hunting safety requirements and initiating amendments to the relevant legislation. [ABSTRACT FROM AUTHOR]

The aim of the study was to compare the productivity and logging costs using the small class harvester Vimek 404 T5 in thinning of birch plantations and young coniferous stands. It was found in the study that due to a lower fuel consumption, maintenance costs and initial investment, the cost of a working hour of the harvester Vimek 404 T5 is significantly smaller than the cost of a working hour of the middle class harvester. The study confirmed that Vimek 404 T5 is a suitable harvester for thinning in a birch plantation; the study also confirmed the previous conclusions about the main advantages of Vimek harvester compared to a middle class harvester in the first thinning - low fuel consumption and costs of maintenance, high productivity and equipment compactness, which allow to reduce the strip road area. The average productivity for Vimek 404 T5 in birch plantation was 6.2 m³ per productive hour, but in young conifer stand the productivity was 4.9 m³ per productive hour. The average stem volume in the birch plantation was 0.06 m³, but in conifer stand 0.05 m³. Productivity for the same dimension trees in the birch plantation is not significantly different from the data obtained in the thinning of the coniferous stands. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the impact of the harvester cutting head feed roller type on the mechanical damages of processed roundwood timber in post manufacturing. The study presents the comparison of the gentle Moipu plate wheel rollers and conventional feed rollers having bigger spikes (hereinafter named - conventional feed rollers). The total amount of segments processed with the gentle Moipu plate wheel rollers was 2199, whereas the amount of segments processed using the conventional feed rollers was 5308. When processing roundwood with the gentle feed rollers, in the 1st flow 8.2% of timber was rejected as substandard due to defects. The corresponding figure in the 2nd flow was 5.2% of the material in which the damage in the form studs was caused by the feed rollers. When processing the timber with conventional feed rollers, the percentage of the damage - dents caused by these rollers in the 1st flow was 26.7%, in the 2nd flow - 43.7% and in the 3rd flow only 2.7%. Using the method of characteristics proportion comparison, significant differences have been observed between feed rollers (t = 17.8 > t0.05;∞ = 1.96). [ABSTRACT FROM AUTHOR]

Tracked forwarders is one of the solutions for the forest soils with poor bearing capacity providing ability to use well-known technology for reasonable cost to improve accessibility of forest resources. Tracked forwarders are not common in forest nowadays and only a few models are produced serially. The ProSilva F2/2 is a new middle-class forwarder, whose frontal tracks are replaced with big tires, ensuring large contact surface, increased mobility of the machine and significantly reduced mass without loosing the load capacity (15 tonnes). The aim of the study was to evaluate productivity, soil impact and cost of the roundwood forwarding using the ProSilva F2/2. The study was conducted in Finland. Productivity (time per crane cycle, split into operations and loads), load size, depth of ruts and soil compaction were estimated during the study. According to the study results, the average productivity is 16 m³ per hour (driving distance to a landing site 200 m, driving speed 2.8 km h-1, average load 9.7 m³). The productivity can be significantly increased by more efficient utilization of the load capacity and by using gripper with the tilt function. The length of ruts on peat soil (56 m ha-1) do not exceed the permitted threshold values in Latvia. The compaction of soil took place mainly in topsoil, no changes in soil density were observed in deeper soil layers. The prime cost of forwarding according to the preliminary estimates is 2.5 € m-3 if the annual production is at least 62000 m³. Utilization rate is important to keep forwarding cost low. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate potential uses of Kranman Bison 10000 6WD forwarder in stands, where roundwood is extracted with a chainsaw and Vimek 404 T5 harvester in normal and difficult forwarding conditions. Productivity of Kranman forwarder was compared with medium-sized John Deere 810 forwarder under normal conditions. In total 230 loads were forwarded during the study, including 63 loads from areas, harvested with a chainsaw, and 167 loads from areas, harvested with Vimek 404 harvester. The average forwarded load is 2.0 m3 (the maximum load is 2.5 m3 therefore the average load capacity is 80%). In average 33 minutes of productive work time were spent by forwarding one load (the proportion of productive working time is 94% from total engine hours of the machine). The average length of forwarding road in trials is 286 m. In normal conditions forwarding of 1 m3 of roundwood extracted with a chainsaw takes 15 minutes of productive working time, but in difficult forwarding conditions the time consumption increases by 13%. The average forwarder fuel consumption is 1.8 L per hour. Accordingly, 0.8 L of fuel are consumed to forward 1 m3 roundwood. In comparison, John Deere 810 under similar conditions consumed 1.6 L fuel to forward 1 m3 roundwood. Study results prove that the best application of Kranman Bison 10000 is forwarding small stands or individual trees logged with a chainsaw. Forwarder can work on soils with low bearing capacity, however productivity can be significantly reduced by stumps and uneven terrain. [ABSTRACT FROM AUTHOR]

Productivity of a harvester significantly affects costs of mechanized felling, which in turn determines, if commercial thinning will be profitable. The objective of this study is to estimate productivity and prime cost of Logset 5HP GT harvester with increased boom length (11 m), equipped with the TH45 felling head, in thinning. Trials are conducted in Latvia, eastern Vidzeme, in coniferous stands. To evaluate productivity of Logset 5HP GT, a time study was carried out. Influence of small trees (diameter at breast height < 8 cm) on productivity and harvesting cost was also determined. During the trials 2379 trees are harvested with the total stem volume of 400 m3. The diameter at breast height of an average harvested tree is 14 cm and volume of a stem - 0.171 m3. Duration of time study is 33.5 h. Obtained productivity rates of Logset 5HP GT are compared with those of John Deere 1070 D harvester. According to the study results average productivity of Logset 5HP GT harvester in thinning of coniferous stands is 13.85 m3 per productive work hour. Prime cost of harvesting of the Logset 5HP GT in thinning is 8.02 € m-3. Increased boom length allows to decrease the total time spent for driving in a stand by 71%. Harvesting of small trees reduces productivity by 6.9% and increase production cost by 2.1% in the experimental stands. Difference between productivity of Logset 5HP GT and John Deere 1070 D in similar conditions is statistically insignificant. [ABSTRACT FROM AUTHOR]